Device for the production of artificial filaments by the melt spinning method



Dec. 19, 1967 .1. P. NOMMENSEN ETAL 3,358,326 DEVICE FOR THE PRODUCTION OF ARTIFICIAL FILAMENTS BY THE MELT SPINNING METHOD Filed Dec. 1, 1965 2 Sheets-Sheet 1 19 17 & ,/3

18 FIGJ Defl 1967 J. P. NOMMENSEN ETAL 3,358,326

DEVICE FOR THE PRODUCTION OF ARTIFICIAL FILAMENTS BY THE MELT SPINNING METHOD Filed Dec. 1, 1965 2 Sheets-Sheet 2 N b f 14 5A um er 0 filaments H63 --r- AI'L10 Number of FlGA filaments 7O 75 8O 85 9O 95 100 I05 110 An.1O

United States Patent O 3,358,326 DEVICE FOR THE PRODUCTION OF ARTIFICIAL FILAMENTS BY THE MELT SPINNING METHOD Johan P. Nomrnensen, Stein, and Hendrik Waning, Geleen, Netherlands, assignors t Stamicarbon N.V., Heerlen, Netherlands Filed Dec. 1, 1965, Ser. No. 510,925 Claims priority, application Netherlands, Dec. 3, 1964, 6414,014 Claims. (Cl. 18-8) ABSTRACT OF THE DISCLOSURE For introducing a linear stream of cooling air into the quenching chamber of a device for producing artificial filaments by melt spinning, a plenum chamber separated from the quenching chamber by a foraminous wall; the plenum chamber having a symmetric baflle between the air inlet to the plenum chamber, and the foraminous wall, which bafile extends the height of the plenum chamber, running approximately parallel to the foraminous wall and terminating an equal distance from each of the two side walls, and an additional wall of foraminous material extending in opposite lateral directions from that symmetry line of the baifle which faces the first-mentioned foraminous wall. In one embodiment, one or more deflectors mounted in the plenum chamber, being adjustable toward and away from the air inlet to the plenum chamber in order to vary the deflection of air toward the foraminous wall.

The foregoing abstract is not intended to be a comprehensive discussion of all of the principles, possible modes or applications of the invention disclosed in this document and should not be used to interpret the scope of the claims which appear at the end of this specification.

The present invention relates to a device for the production of artificial filaments by the melt spinning method, in which one or more spinnerets debouch into a quenching chamber one of the walls of which consists of a number of parallel layers of foraminous material separating the quenching chamber from an adjoining plenum chamber whose bottom is connected to an air supply system, the two side walls of the quenching chamber being normal to the foraminous wall. The filaments issuing from each spinneret comprises a viscous liquid heated above its melting point. Cooling of this liquid takes place in the quenching chamber, where conditioned fluid, for instance air, is blown against the bundle of filaments in a direction normal to the filaments. After the direction of flow of the cooling air has been changed by 90 in the plenum chamber, the air current enters the quenching chamber through the foraminous wall. The filaments pass through the quenching chamber in a direction parallel to the foraminous wall. It is generally assumed that when this cooling method is applied the filaments have a solid skin at a distance of about 50 centimeters beyond their point of issuance from the spinneret. Naturally, the filaments are highly vulnerable, especially as long as they are in the liquid phase, to slight turbulence in the air current which will detract from the uniformity, the stretchability (orientation capacity), and hence from the strength of the yarn produced from such filaments. The foraminous wall serves the purpose of ensuring that the cooling air supplied normal to the direction of the spun filaments traverses the quenching chamber throughout its height and width at uniform rate and without turbulence, so that the resulting filaments have as nearly as possible uniform properties throughout their whole length.

The Dutch patent specification No. 92,197 proposes to construct the foraminous wall of a number of foraminous layers of diiierent mesh lying against each other, the mesh in the direction of flow becoming successively larger and smaller. Apart from the fact that great care has to be exercised to ensure the correct order in using such a large number of layers of differing mesh, this solution is rather expensive. In addition, such a pack will have a very high air resistance.

Accordingly, it is an object of the present invention to provide a cheaper and simpler solution to the problem of introducing a linear stream of cooling air into the quenching chamber of apparatus of the type described.

It is a further object of the invention to equip the plenum chamber of apparatus of the type described in such a way that a desirably uniform distribution of the air is promoted and turbulence in the quenching chamber is prevented.

More specifically, it is an object according to the invention to provide the plenum chamber of a device of the type mentioned in the above with a symmetric bafile between the air inlet and the foraminous wall, which bafile extends the height of the plenum chamber, running approximately parallel to the foraminous wall and terminating an equal distance from each of the two side walls, and to provide an additional wall of foraminous material extending in opposite lateral directions from that symmetry line of the bafile which faces the first-mentioned foraminous wall.

Another object of the invention is the provision in apparatus of the type described of one or more deflectors mounted in the plenum chamber, being adjustable toward and away from the air inlet to the plenum chamber in order to vary the deflection of air toward the foraminous wall.

These and other objects of the present invention as well as its principles and scope of applicability will become more clearly apparent during the course of the following detailed discussion having reference to the embodiments shown in the attached drawings.

In the drawings:

FIGURE 1 is a longitudinal sectional view of a device embodying the invention.

FIGURE 2 is a cross sectional View taken along the line Ii-II in FIGURE 1;

FIGURE 3 is a corresponding cross-sectional view to FIGURE 2 of a slightly modified embodiment;

FIGURE 4 is a histogram illustrating variation in refraction index among individuals in a sample of filaments produced on comparable prior art apparatus not embodying the principles of the present invention; and

FIGURE 5 is a histogram illustrating variation in refraction index among individuals in a sample of filaments produced on apparatus constructed in accordance with the principles of the present invention.

As seen in FIGURE 1, the spinning unit 1 (which includes a spinning pump, not shown in the drawing) at the bottom thereof includes at least one spinneret 2 with spinning orifices (not shown in detail). Under the spinneret 2, there is a quenching chamber 3, which is separated from the adjoining plenum chamber 4 by a foraminous wall 5. The foraminous wall 5 is composed of two parallel foraminous screens 5A and 5B, which in the embodiment shown here are at a distance of 26 millimeters from one another and have a mesh of 250 holes per running decimeter.

The plenum chamber 4 is provided with two side walls 40 and 41, which are at right angles to the foraminous wall 5, and with a curved back wall 42. In the bottom 43 of the plenum chamber there is a round air inlet 6 that can be connected to an air supply system not further indicated in the drawing. Around the air inlet opening 6 there is a short cylindrical pipe 7, having a length of for instance 10 centimeters. In order to promote a better distribution of the air introduced into the plenum chamber, foraminous piece 8 is preferably placed in the plane of the air inlet opening. In .the embodiment shown, this foraminous piece is a disk shaped screen having a'mesh of 130 holes per running decimeter.

Around thepipe 7 is mounted'a vertical arcuate bafiie 9, the base of which surrounds about one-third of the circumference of the air inlet opening. The baffle 9 extends the height of the plenum chamber 4, its convex side facing the foraminous wall 5. Between each side wall 40, 41 of the plenum chamber 4 and the edges '90, 91 of the baflie 9, there is a narrow slit, 10 and 11, respectively, having a Width of 'a few centimeters. Through these slits 10 and 11, allof the blowing air is passed. From the line of symmetry 92 'on the convex side of the baffle 9, two

'foraminous wall segments 13 and 14 extend up to the edges of the foremost forarninous layer A of the foraminous walls, so that a prism is formed by the foraminous pieces'SA, 13 and 14 which has the said line 92 for an edge. Along the center line of the baffle 9, a vertical bafiie strip 15 extends within the foraminous prism in a direction normal to the foraminous wall 5, which strip assists in properly directing the air current.

The back wall 42 of the plenum chamber 4 is fitted with two deflectors '16 and 17 at different levels. These deflectors can be moved vertically along a rail 18, and can be fixed in position by means of a screw 19.

The quenching chamber 3 shown inFIGURES 1 and 2 is of the type having its side walls 30 and 31 curved more or less in an S shape, each being hinged to the plenum chamber 4. At the start of spinning these walls may be open while after the initial spinning stage'is over, they are closed, leaving a narrow, slit-like opening. However, the invention is not restricted to use with apparatus of this specific type, but can be employed with other quenching chambers as well.

The bottom of the quenching chamber 3 is situated over the tube 20, through which the spun filaments are conducted to collecting devices not shown in the draw- The levels at which the deflectors 16, 17 are fixed are preferably chosen so that of the total quantity of air introduced one-third is deflected by the lower deflector 16 and one-third by the upper deflector 17 from along the back wall 42 toward the slits and 11. In a test, a device constructed as shown in FIGURES 1 and 2, was operated as described above and the velocity profile of 'the air current issuing from the foraminous wallS was measured with a hot wire anemometer while the sidewalls ofthe quenching chamber were open, the measurements being made at every tenth centimeter vertically and every centimeter'horizontally. Both at a set mean air flow rate of 0.29 rn./sec. and at a set mean rate of 0.60. m./sec. the velocity distribution of the issuing blowing air proved to be very satisfactorily uniform. The said mean velocity values correspond to such velocities at the opening between the two c'losed quenching chamber doors, where in normal practice such measurements are usually made during operation.

The refraction indices of the filaments spun, then quenched as described using apparatus constructed in accordance with the invention were optically measured and the small spread in the values of the difference, An, of the refraction indices in the longitudinal and transverse directions found in these measurements clearly demonstrated the favorable influence of the uniform air distribution on the preorientation ofthe filaments. FIGURES 4 and 5, which are histograms showv a comparison of the spread, An, in refraction indices and the number of filaments, before andafter application of the invention.

In summary, preferably thebaffle 9 is given the shape 1 of a cylindrically or otherwise arcuately curved surface whose convex side faces the foraminous walls and partially circumscribes the periphery of the air inlet, while two identical foraminous wall segments provided in the plenum chamber 'form an isosceles prism with the "firstmentioned foraminous wall.

The composite prism-shaped foraminous wall 13, 14, 5 in which the successive foraminous layers as seen in the direction offiow have 135, 25.0, and 250.holes.per running decimeter has proved to beparticularly useful.

In .order to effect a uniform rate of flow of the air entering thelplenum chamber, a short cylindrical conduit may be provided around the inlet opningin-thebott0m of the plenum chamber; one or morepieces'of screening, preferably being provided in the inlet opening.

To promote a proper directing of the air current, a bafile strip normal to the baffle 9 may be provided in the foraminous prism in the center of that side of the baffle 9 which faces the foraminous wall 5.

The device according to the invention proves to have a very low air resistance,-compared .to comparable prior art apparatus.

The device according to the invention is not restricted to the-embodiment shown in FIGURES 1 and .2..FIG- URE 3, for instance, is a cross-section of a slightly modified-device in which the batfie 9' has more or less a V shape, and a single'foraminous layer (13', 14') extending up to the two side walls of the plenum chamber4'has been placed against the apex of the V.

From the foregoing, it should now be apparent, that the embodiments described accomplish each of the objects of the present'invention' set forth hereinbefore and clearly illustrate its principles. Becausethese embodiments canbe modified Without departing from theprinci- 'ples of the invention or failing to accomplish its objects the present invention should be understood as encompassing all such modifications as are within the spiritv and scope of the following claims.

We claim:

.1. Apparatus for quenching melt spun synthetic filaments comprising wall means defining a quenching chamber having inlet means for receiving just spun synthetic filaments into said quenching chamber and outlet means for issuing the synthetic filaments from said quenching chamber after they have been quenched;wall means defining a plenum chamber adjoining said quenching chamber, said wall means'including a first foraminous wall between said quenching chamber and said plenum chamber through which the plenum chamber communicates with the quenching chamber; inlet means for admitting fluid to said plenum chamber for transit through said 'first foraminous wall and into said quenching chamber; the plenum chamber wall means comprising two opposed sidewalls adjoining the opposite lateral extremes of said first foraminous wall; a quenching fluid-impervious bafile symmetrically mounted in said plenum chamber with respect to an imaginary centerline plane extending parallel to the direction of travel of the synthetic filaments through the quenching chamber and normal to the first foraminous wall; said baflie extending throughout substantially the full height of the plenum chamber and being interposed'between the fluid inlet means and the first foraminous wall; said baflie being approximately parallel to the first foraminous wall and terminating short of said opposed sidewalls to define two gaps, one-at each lateral edge thereof; and a second foraminous wall, mounted .within said plenum chamber-between the baffle and thefirst 'foraminous wall, and extending substantially from the-intersection of said centerline. planeand said baffle to said two opposed sidewalls, wherebyfluid passing from said plenum chamber into said quenching. chamber must pass around said baflie through said gaps then through said second and said first foraminous walls.

2. The apparatus of claim 1- wherein said baffle is arcuate about an imaginary line in said centerline-plane and convex toward the first foraminous wall.

3. The apparatus of claim 2-wherein the inlet means for admitting fluid to the plenumchamber comprises a circular opening; and wherein the bafiie, adjacent said centerline plane, partially circumscribes the periphery of said circular opening.

4. The apparatus of claim 1 wherein the second foraminous wall defines an isosceles prism with the first foraminous wall.

*5. The apparatus of claim 4 further including a second baflle extending in said centerline plane within said isosceles prism from the juncture of the centerline plane and second foraminous wall at least part way toward the first foraminous wall.

6. The apparatus of claim 1 wherein the first foraminous wall comprises a plurality of layers, the layers comprising the first foraminous wall being two screens each having a mesh of 250 holes per running decimeter and the second foraminous wall being a screen having a mesh of 135 holes per running decimeter.

7. The apparatus of claim 1 wherein the inlet means for admitting fluid to the plenum chamber comprises a circular opening, and further including a short cylindrical conduit received in said opening adjoining the periphery of the opening and extending into and terminating within the plenum chamber; said conduit being bridged by at least one foraminous disk.

8. The apparatus of claim 1 further including at least one deflector mounted in said plenum chamber and arranged to deflect fluid from said inlet means for admitting fluid toward said first foraminous wall.

9. The apparatus of claim 8 wherein said deflector is adjustable toward and away from said inlet means for admitting fluid.

10. In a device for the production of artificial filaments 6 by the melt spinning method, in which one or more spinnerets debouch into a quenching chamber, said device comprising a quenching chamber separated from a plenum chamber by a separating wall consisting of "a plurality of layers of foraminous screening, the plenum chamber having two side walls normal to the said separating wall and an air supply system connected to the bottom of the plenum chamber; wherein the improvement comprises: an 'air impervious baflle symmetrically disposed between said air inlet and said separating wall, said bafl'le extending to the height of the plenum chamber and being spaced an equal distance from each of the side walls of the plenum chamber; said baflie so being disposed so that a line joining two corresponding points on either side of the line of symmetry of the bat-lie is parallel to the said separating wall; at least one deflector being mounted on the rear wall of the plenum chamber in such orientation as to deflect air from the plenum chamber around the edges of the baflle, through the separating wall and into the quenching cham- 20 her, and at least one foraminous screen extending from the line of symmetry of said baflle towards the side walls of the plenum chamber.

References (Iited UNITED STATES PATENTS 2,252,684 8/1941 Babcock 18-8 2,947,029 8/ 1960 Bakker 18-8 3,070,839 1/ 1963 Thompson. 3,169,271 2/1965 Musser 188 WILLIAM J. STEPHENSON, Primary Examiner. 

1. APPARATUS FOR QUENCHING MELT SPUN SYNTHETIC FILAMENTS CONPRISING WALL MEANS DEFINING A QUENCHING CHAMBER HAVING INLET MEANS FOR RECEIVING JUST SPUN SYNTHETIC FILAMENTS INTO SAID QUENCHING CHAMBER AND OUTLET MEANS FOR ISSUING THE SYNTHETIC FILAMENTS FROM SAID QUENCHING CHAMBER AFTER THEY HAVE BEEN QUENCHED; WALL MEANS DEFINING A PLENUM CHAMBER ADJOINING SAID QUENCHING CHAMBER, SAID WALL MEANS INCLUDING A FIRST FORAMINOUS WALL BETWEEN SAID QUENCHING CHAMBER AND SAID PLENUM CHAMBER THROUGH WHICH THE PLENUM CHAMBER COMMUNICATES WITH THE QUENCHING CHAMBER; INLET MEANS FOR ADMITTING FLUID TO SAID PLENUM CHAMBER FOR TRANSIT THROUGH SAID FIRST FORAMINOUS WALL AND INTO SAID QUENCHING CHAMBER; THE PLENUM CHAMBER WALL MEANS COMPRISING TWO OPPOSED SIDEWALLS ADJOINING THE OPPOSITE LATERAL EXTREMES OF SAID FIRST FORAMINOUS WALL; A QUENCHING FLUID-IMPERVIOUS BAFFLE SYMMETRICALLY MOUNTED IN SAID PLENUM CHAMBER WITH RESPECT TO AN IMAGINARY CENTERLINE EXTENDING PARALLEL TO THE DIRECTION OF TRAVEL OF THE SYNTHETIC FILAMENTS THROUGH THE QUENCHING CHAMBER AND NORMAL TO THE FIRST FORAMINOUS WALL; SAID BAFFLE EXTENDING THROUGHOUT SUBSTANTIALLY THE FULL HEIGHT OF THE PLENUM CHAMBER AND BEING INTERPOSED BETWEEN THE FLUID INLET MEANS AND THE FIRST FORAMINOUS WALL; SAID BAFFLE BEING APPROXIMATELY PARALLEL TO THE FIRST FORAMINOUS WALL AND TERMINATING SHORT OF SAID OPPOSED SIDEWALLS TO DEFINE TWO GAPS, ONE AT EACH LATERAL EDGE THEREOF; AND A SECOND FORAMINOUS WALL, MOUNTED WITHIN SAID PLENUM CHAMBER BETWEEN THE BAFFLE AND THE FIRST FORAMINOUS WALL, AND EXTENDING SUBSTANTIALLY FROM THE INTERSECTION OF SAID CENTERLINE PLANE AND SAID BAFFLE TO SAID TWO OPPOSED SIDEWALLS, WHEREBY FLUID PASSING FROM SAID PLENUM CHAMBER INTO SAID QUENCHING CHAMBER MUST PASS AROUND SAID BAFFLE THROUGH SAID GAPS THEN THROUGH SAID SECOND AND SAID FIRST FORAMINOUS WALLS. 